As regards the others let me recommend to you the complete description of them given by Posey in A System of Ophthalmic Operations. Let us consider the first of the three procedures just mentioned iridectomy introduced by von Graefe. The mechanism of its mode of cure is best studied in cases of acute primary glaucoma, when there is apposition of the periphery of the iris to the cornea.
As far as the Lagrange procedure is concerned, you will remember that after eserinization an oblique incision is made through the sclera by means of a narrow Graefe knife and a large conjunctival flap secured.
A small shaving of the sclera, about ½ mm. thick, 1½ to 2 mm. broad and from 2 to 3 mm. long, is then excised by means of a narrow Graefe knife. The scleral slip is then freed from the conjunctiva at each end and the mucous membrane brought together over the wound by fine catgut sutures.
These effects are probably due to a central excitation of a similar nature to that produced by santonin. Persons thus attacked complain, shortly after the injection, of an intensely sour or bitter taste, which for the most part ceases after elimination of the morphin. Von Graefe and Sommerfrodt speak of a spasm of accommodation occurring after ingestion of medicinal doses of morphin.
Once it was Meier Graefe from Berlin, big, handsome, enterprising, not yet encumbered with Post-Impressionism and its outshoots, seeking American and British contributors to the German Pan, a magazine as big and enterprising as himself if not always as handsome, and the younger generation of London had the comfort of knowing that if the Victorian door in England held firm, the door of Europe had opened to them.
This being the case one cannot truthfully say that trephining alone can take the place of the old Graefe iridectomy. On the other hand, trephining may with advantage be employed instead of iridectomy for cases difficult or dangerous under the latter method.
As you are well aware, numerous operators regard the Lagrange operation as superior to the iridectomy of von Graefe because they believe there is filtration through the newly formed tissue between the lips of the operative wound.